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23B-018 780 CMR 419 Live WorkSECTION 419 LIVE/WORK UNITS 419.1 General. A live/work unit is a dwelling unit or sleeping unit in which a significant portion of the space includes a nonresidential use that is operated by the tenant and shall comply with Sections 419.1 through 419.8. Exception: Dwelling or sleeping units that include an office that is less than 10 percent of the area of the dwelling unit shall not be classified as a live/work unit. These provisions allow a live/work unit that includes both living and working environments to be considered a single Group R-2 dwelling for application of the code. Several limitations and specific requirements are applied to both the living portion of the unit and the work portion of the unit. Prior to the adoption of these provisions, the code and the IRC did not allow residential live/work units in a form that is typically desirable for community development. This concept has become increasingly popular allowing design and construction of a public business, with employees working within a residence, allowing the public to enter the work area of the unit to acquire service. Examples of live/work commercial functions are artist’s studios, beauty parlors, nail salons and chiropractor’s offices. It is important to note that live/work is specifically not to apply to an in-home office (architect home office, consultant home office, etc.). The exception to Section 419.1 is intended to address these small home offices which involve less than 10 percent of the dwelling. These concepts are throwbacks to an era of planning which created a community where residents could walk to all needed services such as the typical corner commercial store. Examples of this form of planning can be found in many older cities, as well as many “planned communities.” Live/work units began to re-emerge in the 1990s through a development style known as “Traditional Neighborhood Design” (TND). More recently, adaptive reuse in many older urban structures in city centers incorporated the same live/work tools to provide a variety of business offerings combined with residential unit types. Historically, building codes did not have to deal with many live/work issues because zoning codes generally precluded a mixing of uses within a neighborhood, much less within a building. However, recent planning trends have been adopted in many jurisdictions, encouraging mixing of commercial and residential uses, not just in neighborhoods, but also in buildings, and even within unit types, such as the live/work unit commonly found in TND projects. The live/work approach is also driven by the desire to provide affordable housing. Many cities and towns also aggressively pursue affordable housing, with the IRC being a key tool in this effort. The IRC allows jurisdictions to produce a range of housing types at competitive market values, including the live/work unit. However, there are no provisions for any use other than residential in the IRC. Since live/work units mix in a commercial use, they are driven out of the IRC into the code. In previous editions of the code, when this happens, the live/work units incur an increase in coderelated construction requirements (use separation, construction type, egress, fire prevention) in excess of any risk present in the work function. The added requirements drive construction costs up, and inevitably drive the units out of the affordable housing range. The provisions in the 2009 code for live/work units apply to the code criteria based on the Group R-2 provisions for construction. The occupant loads will be determined by the “function” of each space in accordance with Table 1004.1.1. In the new IRC, there is an exception to Section R101.2 that allows live/work units complying with Section 419 of the code to be constructed in accordance with the IRC. The concept of live/work units being unseparated is dependent on how mixed use is applied. Section 419 allows mixed use unseparated occupancies within the dwelling unit or sleeping unit as long as it meets the limits within this section. It is then to be classified as a Group R-2 occupancy. In previous codes, any combination of occupancies would have to be treated as a mixed use condition and would be considered either separated or nonseparated in accordance with the code. The building must then be classified in both occupancies and meet the more restrictive requirements for both. Under the new live/work requirements, the building is treated only as a Group R-2 occupancy despite including work environments. Special features that are common within a dwelling unit and are likely within the live/work unit are addressed in order to clearly delineate the means for designing a live/work unit 419.1.1 Limitations. The following shall apply to all live/work areas: 1. The live/work unit is permitted to be a maximum of 3,000 square feet (279 m2); 2. The nonresidential area is permitted to be a maximum 50 percent of the area of each live/work unit; 3. The nonresidential area function shall be limited to the first or main floor only of the live/work unit; and 4. A maximum of five nonresidential workers or employees are allowed to occupy the nonresidential area at any one time. These provisions were meant to apply strictly to small businesses associated with dwelling and sleeping units. In fact the intent is that the main occupancy of the building is residential with some business activity within the building. The code limits the nonresidential aspect to a maximum of 50 percent of the area of each unit. In addition, the total area of the live/work unit is limited to 3,000 square feet (279 m2). Therefore, the total area of the work unit would be a maximum of 1,500 square feet (139 m2). Since a nonresidential use is being located in a dwelling unit or sleeping unit, the nonresidential area is limited to the first or main floor. Therefore, those coming to the place of business do not need to enter the residential portion of the building. Finally, in keeping with the intent that these are small occupancies and that such occupancies could not create unnecessary life safety concerns, the number of nonresidential workers (employees) is limited to five. This limit of five is not the limit on the number of occupants that can be located within the work area, but simply the number of workers from outside the household that can be there on a regular basis. The 1,500- square-foot (139 m2) limit on area would limit the number of occupants based upon the occupant load factors. 419.2 Occupancies. Live/work units shall be classified as a Group R-2 occupancy. Separation requirements found in Sections 420 and 508 shall not apply within the live/work unit when the live/work unit is in compliance with Section 419. High-hazard and storage occupancies shall not be permitted in a live/work unit. The aggregate area of storage in the nonresidential portion of the live/work unit shall be limited to 10 percent of the space dedicated to nonresidential activities. The entire live/work unit is to be classified as Group R-2 regardless of the types of business being conducted. This exempts such units from the requirements for separation in Sections 420 and 508 within the unit, but would still require the separation between each live/work unit. The provisions that prohibit high-hazard and storage occupancies intend to avoid the accumulation of excessive and dangerous fire loads in residential related occupancies. This section would not prohibit the occupancy from containing the maximum allowable quantities of hazardous materials per control area within a building. Control areas are regulated in Section 414 (see the commentary for that section). Storage is always a potential fire load with any business and to ensure that it does not become a large fire hazard it is limited to 10 percent of the nonresidential portion of the live/work unit. That would be a maximum of 150 square feet (14 m2)—about the size of a large closet. 419.3 Means of egress. Except as modified by this section, the provisions for Group R-2 occupancies in Chapter 10 shall apply to the entire live/work unit. This section requires compliance with Chapter 10 for means of egress unless the general requirements are modified by the following four subsections. This will address exiting requirements for both the Group R-2 occupancy and additional requirements for the nonresidential activity and the general public in such areas where they occur. 419.3.1 Egress capacity. The egress capacity for each element of the live/work unit shall be based on the occupant load for the function served in accordance with Table 1004.1.1. The egress capacity must be based upon the actual use of the space. Therefore if you had a mercantile type use in the live/work unit, the egress capacity must be based upon 30 square feet (2.8 m2) per person of the gross area of the mercantile space. If a 3,000- square-foot (279 m2) unit is equally divided for mercantile and residential use, in such a case the calculated occupant load would be determined by dividing the area by the square feet per person: 1,500 square feet/ 30 square feet (18.5 m2) per person = 50 occupants. In addition, the capacity for residential use is 200 square feet per person (gross area), which would be 1,500 square feet/200 square feet per person = 8 occupants. 419.3.2 Sliding doors. Where doors in a means of egress are of the horizontal-sliding type, the force to slide the door to its fully open position shall not exceed 50 pounds (220 N) with a perpendicular force against the door of 50 pounds (220 N). Section 1008.1.2, Exception 4, allows the use of sliding doors in Group R-2 occupancies. This section continues this allowance of such doors in live/work units, but puts an upper limit on door-opening force of 50 pounds (220 N). This is greater than the door-opening force indicated for sliding doors in Section 1008.1.3. 419.3.3 Spiral stairways. Spiral stairways that conform to the requirements of Section 1009.9 shall be permitted. Spiral staircases are allowed in dwelling units and this section simply emphasizes this allowance with a specific reference back to the section with the design criteria in Chapter 10. 419.3.4 Locks. Egress doors shall be permitted to be locked in accordance with Exception 4 of Section 1008.1.9.3. This section allows the use of dead bolts, night latches or security chains in live/work units with an occupant load of 10 or less. If the occupant load is greater than 10, other exceptions for locking devices may be applicable, as indicated in Section 1008.1.9.3, Exception 2. 419.4 Vertical openings. Floor openings between floor levels of a live/work unit are permitted without enclosure. One of the problems with the prior codes when designing and constructing a live/work unit was the requirement for enclosure of exit stairways. For ease of access, the live/work units can have open interior stairways for the residential and nonresidential portions of the dwelling unit, similar to a multiple-story dwelling unit (see Section 1022, Exception 3). If the units are separated and do have enclosed stairways, they would be treated as any other residential stairway enclosure within a dwelling unit; and no fire-resistant- rated construction is required. 419.5 Fire protection. The live/work unit shall be provided with a monitored fire alarm system where required by Section 907.2.9 and an automatic sprinkler system in accordance with Section 903.2.8. Since the unit is considered as Group R-2, the entire building would be required to be sprinklered in accordance with any of the three sprinkler standards, as appropriate. Note that the IRC Section 101.2 exception explicitly allows the use of NFPA 13D. The code requirements provide only a general reference to Group R sprinkler requirements. Live/work units are not specifically addressed; however, single-family homes, duplexes and townhouses are listed under Section 903.3.1.3. This section requires the installation of a fire alarm system as required for a Group R-2 occupancy. Section 907.2.9 would only require a fire alarm system in certain cases. The requirements for a manual fire alarm are based upon the location of the Group R-2 dwelling unit (three or more stories above the lowest level of exit discharge or one story below the highest level of exit discharge) and the number of units (more than 16). If a building has a sprinkler system and would require a manual system, the manual aspect is no longer required. Instead the sprinkler system is required to be tied to the notification appliances and activate the system upon water flow. 419.6 Structural. Floor loading for the areas within a live/work unit shall be designed to conform to Table 1607.1 based on the function within the space. Since live/work units may have structural loads not normally anticipated by Group R-2 occupancies, the code specifically requires structural design of floor loadings to be addressed in accordance with Table 1607.1, based upon what is actually occurring in the space. For instance, if the nonresidential activity is a business, there may be equipment such as computers, files or a large copy machine which code specifically requires structural design of floor loadings to be addressed in accordance with Table 1607.1, based upon what is actually occurring in the space. For instance, if the nonresidential activity is a business, there may be equipment such as computers, files or a large copy machine which requires loading based on office loads of 100 psf (4788 Pa). 419.8 Ventilation. The applicable requirements of the International Mechanical Code shall apply to each area within the live/work unit for the function within that space.